This is mathematic`s tricks,right? When you do not make those moves,like2+3 and so on,gopher is wrong... this is something with numbers..... But for us easier to believe in magic and don`t try to explain it..... But this is such a good game)

It doesn't matter if you move the mouse on not :) Maybe, when you move the mouse, you get it wrong.
It's just a math trick. The ONLY NUMBERS YOU CAN GET are devideable by 9. And all of them have the same symbol XD